After an enterprise activation is completed, some calendar entries in the Microsoft Office 365 mailbox may be missing on the smartphone device.

Any Calendar items that do have a GOID (Global Object ID) property should sync correctly during a calendar slow sync, however, entries that are missing the GOID property will not sync.

Microsoft Outlook and Microsoft Outlook Web Access add a GOID value to calendar items by default so any new calendar items or calendar items modified in Microsoft Outlook after the migration should automatically sync to the smartphone device.

Copy Calendar to the PST file in Outlook (instead of using export option).

Remove Calendar entries in Office 365 mailbox.

Move Calendar items to Office 365 mailbox from the new PST file.For detailed instructions visit the Microsoft Help and Support site and search for:How to move Outlook meetings without losing the option to Send Update, Article KB2167170.

After the account is moved to Microsoft Office 365, activate the smartphone device so that the calendar entries from smartphone device will sync to the Microsoft Office 365 mailbox.

Note: While importing the PST to Microsoft Office 365 mailbox, do not import the calendar database.

Workaround 4

Manually edit the missing calendar entries in Microsoft Outlook.

Workaround 5

To force a synchronization of multiple calendar entries, select multiple entries in Microsoft Outlook and then assign a category to the bulk selection.This will effectively cause a modification to each appointment which will stamp the GOID property and allow multiple items to synchronize.